Engine starter gearing

ABSTRACT

Engine starter gearing of the positive shift type, including a clutch to provide driving, overrunning, means for automatically separating the clutch teeth at a predetermined speed, and means for keeping the clutch teeth in engagement during the indexing function, thereby allowing full and complete engagement of the starter pinion gear into the engine ring gear to prevent damage to the clutch teeth of the starter and starter motor shaft when the starter motor is energized.

United States Patent Mortensen Sept. 16, 1975 [54] ENGINE STARTER GEARING 2,213,934 9/1940 Sekella 74/7 2,728,234 12 1955 V lk, J t l... 74 7 C [75] Inventor: Harold R. Mortensen, Horseheads, o r e a Primary Examiner-Samuel Scott [73] Assignee: The Bendix Corporation, Southfield, Assistant Examiner-Wesley S. Ratliff, .lr.

Mich. Attorney, Agent, or FirmRemy J. VanOphem [22] Filed: Dec. 10, 1973 ABSTRACT [21] Appl' 423,635 Engine starter gearing of the positive shift type, in-

cluding a clutch to provide driving, overrunning, 52 US. Cl. 74/7 c; 123/179 K means for automatically Separating the clutch teeth at [51] Int. Cl. F02n 17/00 a predetermined Speed, and means for keeping the 58 Field of Search 74/6, 7, 7 c, 7 D, 7 E; Clutch teeth in engagement during the indexing func- 123/ 79 tion, thereby allowing full and complete engagement of the starter pinion gear into the engine ring gear to [56] References Cited prevent damage to the clutch teeth of the starter and UNITED STATES PATENTS starter motor shaft when the starter motor is enerd. 1,575,698 3/1926 McGrath 74/7 E glze 1,951,032 3/1934 Nardone 74/7 C 13 Claims, 1 Drawing Figure ENGINE STARTER GEARING BACKGROUND OF THE INVENTION The present invention relates to engine starter gearing of the positive shift type as described in U.S. Pat. No. 3,263,509, entitled Engine Starter Gearing, issued Aug. 2, 1966, and U.S. Pat. No. 1,892,056, entitled Engine Starter, issued Dec. 27, 1932.

More specifically, the present invention relates to engine starter gearing of the positive shift type which provides means for indexing the starter pinion with respect to the ring gear of the engine to be started.

Prior art developments have resulted in engine starter gearing having a unidirectional torque transmitting clutch which includes means for indexing the pinion gear of the starter with the engines ring gear when abutting conditions exist between said pinion gear and the engines ring gear, and means for separating the clutch teeth within the starter when the pinion gear of said starter rotates at a faster speed than the starter motor shaft.

In prior art starters, e.g., U.S. Pat. No. 3,263,509, a condition occurs where upon shifting the starter along the shaft towards the engine ring gear, the pinion moves axially toward the engine ring gear. When the gear teeth on the pinion gear do not axially align with the spaces between the teeth on the engines ring gear, the pinion gear will abut the engines ring gear. After this abutting condition occurs, the starter is designed to move the pinion gear rotatably so that the pinion and ring gear no longer abut and the pinion gear assumes a meshing position with respect to the ring gear. Upon meshing the pinion moves axially forward into the ring gear, while the clutch within the starter moves rotatably and axially forward toward the engine ring gear along a helical spline thereby causing the clutch teeth to separate from each other to a point where they stop on top of each other. At this point the starter motor is energized. Because of the relatively high torque and acceleration of the starting motor, the clutch teeth, which are not completely engaged, cannot mate immediately to carry the torque load developed by the starting motor, and a slipping of the clutch teeth occurs. In some cases, the clutch teeth will only slip one or two teeth and then engage. However, the slipping of the clutch teeth results in excessive wear at the mutually engageable surfaces of the teeth as well as overloading of the starter motor shaft. This overload causes the starter motor shaft to bend and/or twist.

BRIEF SUMMARY OF THE INVENTION This invention provides engine starter gearing of the positive shift type that permits the starter gearing to complete the indexing of the starter pinion with the engine ring gear without separating the clutch teeth, thereby allowing engagement of the starter pinion gear into the engine ring gear without adverse damage to the clutch teeth of the starter and the starter motor shaft.

The invention is an engine starter assembly characterized by an arrangement of the assembly elements whereby the clutch teeth within the assembly are kept in engagement during the complete indexing of the pin ion gear with the engine ring gear while simultaneously permitting rotational movement thereby allowing the pinion of the starter to index and align itself for proper engagement with the ring gear. The starter gearing is further characterized by an intermediate member 50 which is mounted for rotational and axial movement on a first sleeve 20 and a driving clutch member 30 that is mounted for only axial movement with respect to said intermediate member.

In one embodiment of the invention, the starter gearing comprises: an intermediate member 50 having a forward end and rearward end and a means for mounting said intermediate member on a power shaft 5, said means including: means for providing axial and rotational movement of said intermediate member 50 mounted on said shaft; and means for biasing said member in the forward direction so that when an axial force is applied in a rearward direction, said member 50 moves axially and rotatably in a rearward direction and when said force is removed, said member returns to its original position; a driving clutch sleeve 30 having a forward and rearward end, said forward end having axially extending clutch teeth 32; and means for mounting said driving sleeve on said intermediate member, said means including: means for providing axial movement 31 of said driving sleeve 30 with respect to said intermediate member 50; and means for biasing 80, 81 said driving sleeve in the forward direction so that when a force is applied in a rearward direction, said driving sleeve moves axially in a rearward direction and when said force is removed, said driving sleeve returns to its original position; a driver clutch sleeve 40 having radially extending gear teeth 41 on one end portion and axially extending clutch teeth 42 on the opposite end; and means for mounting said driver sleeve on said shaft for rotational and axial movement with respect to said shaft, said driver sleeve 40 disposed so that the clutch teeth 42 of said driver sleeve engage said driving sleeve clutch teeth 32 for transmitting torque between said driving sleeve and said driver sleeve to rotate said driver sleeve; whereby when a rearward force is applied to said driver sleeve, said driver sleeve 40 and said driving sleeve 30 move axially rearward with respect to said intermediate member 50 and said intermediate member 50 moves axially rearward with respect to said shaft.

Accordingly, it is an object of this invention to provide an engine starter that keeps the clutch teeth of the starter in engagement during the indexing of said pinion gear teeth with the engines ring gear.

It is another object of the present invention to provide starter gearing for internal combustion engines which is simple, efficient, reliable and economical to manufacture and fabricate.

It is a further object of this invention to provide starter gearing whereby, during the indexing of the pinion gear with the engines ring gear, the clutch teeth move axially but nonrotatably with respect to each other but together move rotatably with respect to the shaft, so that during the indexing of the starter pinion with the engine ring gear the clutch teeth are kept in engagement.

It is still a further object of the present invention to provide a starter gearing that prevents adverse damage to the clutch teeth of the starter and the starter motor shaft.

The above and other objects and features of the invention will become apparent from the following detailed description taken in conjunction with the accompanying drawing and claims which form a part of the specification. Further, use of numerals is for the purpose of clarification and is not intended to limit the specific embodiment referenced.

DETAILED DESCRIPTION OF THE DRAWINGS Referring to the drawing, there is illustrated a starter drive 2 for an engine, mounted on a power shaft 5 of a starting motor (not illustrated). The drive includes an axially extending first sleeve 20 connected to the power shaft 5 by straight splines 23 on the inside surface of the first sleeve, so as to be axially, but nonrotatably moveable relative to the power shaft. The outside surface of the forward extremity of said first sleeve 20 has helical splines 22 formed thereon to which an intermediate member 50 is moveably mounted. The intermediate member 50 has a passage having a first end portion which includes helical splines 53 mutually engageable with the helical splines 22 of said first sleeve so that said member 50 is rotatably and slidably mounted to said first sleeve 20. The opposite end portion of the passage of said member has straight splines 51.

A second sleeve 100 is coaxially mounted to the power shaft adjacent to said first sleeve 20. Said second sleeve 100 is connected 102 at one end to the forward end of the first sleeve for movement therewith.

A driving clutch sleeve member 30 having straight splines 31 on one portion of the outside surface and axially extending clutch teeth 32 on an opposite end is coaxially disposed with respect to said first 20 and second 100 sleeves. The straight splines 31 on the outside surface are mutually engageable with the straight splines 51 on the intermediate member 50 so that said driving clutch sleeve member 30 is mounted for only axial movement with respect to said intermediate member 50 and mounted for axial and rotatable movement with respect to said first and second sleeves. In its engaged position a portion of the driving clutch sleeve 30 projects past the forward end of sleeve 20 and the rightmost edge of the inside surface includes shoulder 34.

The barrel shaped housing has a first portion 11 and a second portion 12 axially aligned with respect to said first portion. The first portion 11 of said housing 10 has a first end 14 and an opposite end with a narrowed portion 13 which is mounted to the outside end portion 21 of said first sleeve 20. The second portion 12 of said housing has a first annular groove 96 adjacent the first end 17 and a second annular groove 97 adjacent the opposite end 18 of the second portion of said housing. The second portion of said housing is provided with an internal shoulder 19 intermediate its extremities to provide an abutment for the first end 14 of the first portion of said housing.

A driven clutch sleeve 40 is coaxially disposed and rotatably mounted to said second sleeve 100 adjacent to the driving sleeve 30. The driven sleeve 40 has radially extending gear teeth 41 on one end which form a pinion gear, and axially extending clutch teeth 42 on the other end which engage the driving sleeve clutch teeth 32 for transmitting torque so that the driving sleeve 30 may rotate the driven sleeve 40. The driven clutch sleeve 40 includes an internal circular recess 44. The opposing or adjacent faces of clutch teeth 32 and 42 are provided with mutually engageable inclined torque transmitting surfaces 43. The clutch teeth are of a sawtooth variety to provide a unidirectional overrunning clutch connection.

A means for moving the starter gearing assembly 2 toward and away from the engine gear 200 may be comprised of a conventional solenoid, air or hydraulic cylinder actuated lever (not illustrated) connected to the narrowed portion 13 of the first portion of said housing.

An overrunning clutch feature which operates to separate the clutch teeth of the driving sleeve 32 from the clutch teeth of the driven sleeve 42 when the driven sleeve rotates faster than the driving sleeve includes: an annular recess 44 within the driven clutch sleeve an annular ring 62 having an inner inclined surface 66 is backed by a thrust washer 63, abuts at its outer edge the shoulder 34 of said driving clutch sleeve 30. The inner inclined surface 66 of the annular ring is conically formed with respect to the longitudinal axis of the starter gear. A plurality of arcuate centrifugal weight members are annularly arranged adjacent said ring 62. Each weight has an inclined surface 67 complementary with an abutting inclined surface 66 of the annular ring 62. The centrifugal weight members 60 are mounted so that the inclined surface 67 of said centrifugal weight members abut the inclined surface 66 of the annular ring 62. A radial hole 68 is formed in each weight at an intermediate or midpoint closely corresponding with the location of the center of gravity of the weight member and support pin 61 is secured on one end in a radial hole 69 formed in the annular recess of said driven clutch member 40. The pin projects radially inwardly therefrom into the hole 68 in the weight member. The pin and hole connection restrain the weight members from movement in either the axial or circumferential direction, while permitting radial movement in response to centrifugal force.

A bearing sleeve 120 is coaxially disposed with the second sleeve 100 and projects into the annular recess 44 and provides a radially inward stop for the weight member 60, thereby establishing clearance between said weight members 60 and said second sleeve 100 to avoid wear of the moving assembly. The assembly for separating the clutch teeth when the driven sleeve rotates faster than the driving sleeve also includes elements for axially biasing the driven 40 and driving 30 sleeves so that their mutually engageable clutch teeth 32, 42 are in an engaged position until said driven sleeve 40 reaches the predetermined speed required to separate or overrun the clutch teeth. The biasing elements include: a lock ring 93 which is located in the annular notch 97 adjacent the opposite end 18 of the second portion of said housing. The lock ring 93 has sufficient radial length to engage the driven clutch sleeve 40 to thereby confine the driven clutch sleeve within the opposite end of said second housing passage; a block of (shock absorbing) resiliently deformable material 90, such as, rubber, located between the first end of the second portion of said housing and the first end 14 of the first portion of said housing; a lock washer 91 located adjacent the biasing element which abuts a second lock ring 92 located in the annular recess adjacent the first end 17 of the second portion of said housing, so that axial movement in one direction of either portion 10, 12 of the housing with respect to the other will increase the biasing force developed by the material 90. Y

An assembly for keeping the clutch teeth 32 of the driving sleeve 30 in engagement with the clutch teeth 42 of the driven sleeve 40 when the driving sleeve moves in the direction of the driven sleeve comprises: a spring 80, located between the first portion of the housing and the driving clutch sleeve, which acts upon the driving clutch sleeve 30 through member 81 to exert a force upon the driving clutch member 30 in the direction of said driven clutch sleeve 40; a second spring 70 located between the first portion 11 of the said housing and the intermediate member 50 which acts upon the intermediate member 50 to exert a force in the direction of said driving member 30 thereby keeping intermediate member 50 in engagement with said driving clutch member 30. The spring constant of spring 80 is greater than the spring constant k of spring 70. It is desirable that k be at least 1.4 times greater than k, and preferably k about 2 times greater than k,. In actual practice, it has been found that the force exerted by spring 80 acting between the driving sleeve and the housing 10 is about 11 pounds, and the force exerted by spring 70, acting between the intermediate member 50 and the housing 10 is about 5 pounds 2 ounces.

In operation, when it is desired to start the engine, the starter gearing assembly 2 is shifted toward the engine ring gear 200 by a positioning mechanism (not shown) connected to the narrowed portion 13 of the first portion of the housing and along the power shaft 5 so that pinion gear 41 engages the engines ring gear 200. The power shaft (5) is rotated by a starting motor to transmit torque through straight splines 23 to sleeve 20, from helical splines 22 to the intermediate member 50, from the straight splines 51 of intermediate member 50 to the straight splines 31 of the driving sleeve 30, through the mutually engageable clutch teeth 32, 42 driven clutch sleeve 40 pinion gear 41 and to the engine ring gear 200. After the engine starts and becomes self-operative, engine ring gear 200 will now drive the driven clutch sleeve 40 at a speed greater than that of shaft 5. At a predetermined speed, the centrifugal weight members 60 will start to move radially outward along support pins 61. This radial movement causes an axial thrust on the annular ring 62 through incline surfaces 66 and 67. The movement of Weight members 60 in a radial direction along support pin 61 creates a centrifugal force acting on surfaces 66 and 67 which is sufficient to generate an axial force on annular ring 62 to cause annular ring to move in a direction away from the driven clutch sleeve. Thrust washer 63 is thereby caused to move away from the driven clutch sleeve and through its abutting connection at shoulder 34 causes the driving clutch sleeve to become disengaged and moves against the biasing forces of springs 70 and 80 thereby causing separation of clutch teeth 32 and 42 at the predetermined engine self-operating speed. This action prevents the clutch teeth from being subject to periods of contact while the pinion is rotating at a speed greater than that of the power shaft.

The starter gearing is further designed to provide an indexing function when the pinion gear 41 is moved to the right but abuts one of the teeth of the starter gear 200 thereby preventing engagement of the driven gears teeth 41 with the ring gear 200. When abutment occurs axial movement by the driven sleeve is obstructed by the ring gear, but the shifting mechanism, attached at the housings narrowed portion 13, will continue to shift housing 10 toward ring gear 200. In this abutment condition, driven clutch sleeve 40, driving clutch sleeve 30, and intermediate member 50 stand still against ring gear 200 while the first sleeve 20, the second sleeve 100, and the housing first and second portion 10 and 20 continue to shift towards the engines ring gear. The continued axial movement of sleeve 20 forces intermediate member 50 to rotate through the interaction of the helical spline 22 on sleeve 20 and the intermediate members helical spline 53. The rotation of the intermediate member 50 causes driving sleeve 30 also to rotate and since clutch teeth 32 and 42 are in engagement, driven clutch member 40 is also forced to rotate. This rotation during abutment is known as indexing. Indexing will continue until driven sleeve gear teeth 41 rotates sufficiently to clear the engine ring gear teeth. Upon clearing the teeth of the engine ring gear, the gear teeth 41 on the driven clutch member 40 enter into engagement with the teeth on the engine ring gear. At the point of engagement the driving and driven clutch members will be moved axially forward into full engagement with the engines ring gear. Full engagement of the driven clutch gear teeth with the engines ring gear is attained by the axial force generated by spring 80 acting upon the driving and driven clutch sleeves to move the clutch sleeves 30, 40 axially, but not rotatably in the direction of the ring gear 200. The reason that full engagement of the driven sleeve gear teeth with the engines ring gear can be accomplished without separating the clutch teeth is because spring constant k of the spring 80 is larger than spring constant k, of the spring 70. After the driven sleeve gear teeth are fully engaged into the engine ring gear, the starter motor is activated causing shaft 5 to rotate. The helical spline 22 on the first sleeve 20 in conjunction with the axial force generated by spring now causes intermediate member 50 through helical spline 53 to thread itself forward until it stops against the driving sleeve 30. Intermediate member 50 maintains this position until the engine is started.

The starter gearing mechanism accomplishes all of the normal functions of impact cushioning, indexing, overrunning, automatic clutch teeth separation, and in addition, keeps clutch teeth 32 and 42 in full engagement during the Complete indexing function, thereby greatly increasing the life of the starter gearing.

While a preferred embodiment of the invention has been disclosed, it will be apparent to those skilled in the art that changes may be made to the invention as set forth in the appended claims and, in some instances, certain features of the invention may be used to advantage without corresponding use of other features.

Accordingly, it is intended that the illustrated and descriptive materials herein be used to illustrate the principles of the invention and not to limit the scope thereof.

Having discribed the invention, what is claimed is:

1. Starter gearing comprising:

a shaft;

a intermediate member having a forward end and a rearward end;

means for mounting said intermediate member on said shaft, said means including:

means for providing axial and rotational movement of said member mounted on said shaft; and means for biasing said member in the forward direction so that when a force is applied in the rearward direction, said member moves axially and rotatably in a rearward direction and when said force is removed, said member returns to its original position;

a driving clutch sleeve having a forward and rearward end, said forward end having axially extending clutch teeth;

means for mounting said driving sleeve on said intermediate member, said means including: means for providing axial movement of said driving sleeve with respect to said intermediate member; and

means for biasing said driving sleeve in the forward direction so that when a force is applied in the rearward direction, said driving sleeve moves axially in a rearward direction and when said force is removed, said driving sleeve returns to its original position;

a driven clutch sleeve having radially extending gear teeth on one end portion and axially extending clutch teeth on the opposite end; and

means for mounting said driven sleeve on said shaft for rotational and axial movement with respect to said shaft, said driven sleeve disposed so that the clutch teeth of said driven sleeve engage said driving sleeve clutch teeth for transmitting torque between said driving sleeve and said driven sleeve to rotate said driven sleeve;

whereby when a rearward force is applied to said driven sleeve, said driven sleeve and said driving sleeve move axially rearward with respect to said intermediate member and said intermediate member moves rotatably and axially rearward with respect to said shaft, so that when said rearward force is removed said driving clutch sleeve moves in a direction of said driven clutch sleeve while said mutually engageable clutch teeth are maintained in full engagement.

2. The starter gearing recited in claim 1 wherein the means for biasing said intermediate member includes a spring having a spring constant k and wherein the means for biasing said driving sleeve includes a spring having a spring constant k which is greater than k 3. The starter gearing recited in claim 2 wherein k is between 1.5 and 2.7 times the magnitude of k 4. The starter gearing as recited in claim 3 wherein the means for mounting the intermediate member on the shaft for axial and rotational movement of said member includes a helical spline on one portion of said member.

5. The starter gearing as recited in claim 4 wherein the means for mounting said driving sleeve on said intermediate member for axial movement of said driving sleeve with respect to said member includes a straight spline on said driving sleeve that mates with a straight spline on a portion of said member.

6. The starter gearing as recited in claim 5 including:

means for separating the clutch teeth of said driving sleeve from the clutch teeth of said driven sleeve by moving said driving sleeve in a first direction away from said driven sleeve when said driven sleeve rotates above a predetermined speed.

7. Starter gearing comprising:

a barrel shaped housing having a central axis and a passage therethrough, said housing having a first portion and a second portion axially aligned with said first portion; said second portion having a first end and an opposite end; said first portion having a first end and an opposite end having a narrowed portion; and

a first sleeve having an outside end portion mounted to the narrowed portion of said housing, said first sleeve having a helical spline on the other outside end portion, and a straight spline on the inside surface of said sleeve;

' a second sleeve axially aligned with and adjacent to said first sleeve; said second sleeve connected at one end to one end of said first sleeve;

a driving sleeve coaxially disposed with respect to said first and second sleeve, said driving sleeve having a straight spline on one portion of the outside surface and axially extending clutch teeth on one end;

a driven sleeve coaxially disposed and mounted to said second sleeve adjacent to said driving sleeve, said driven sleeve having radially extending gear teeth on one end and axially extending clutch teeth on the other end which engage said driving sleeve clutch teeth for transmitting torque between said driving and driven sleeves to rotate said driven sleeve, said driven sleeve having an annular recess formed on the inside surface of said other end;

a member moveably mounted on said first sleeve, said member having a first end portion, a second opposite end portion, a passage therethrough, a he lical spline at said first end portion of said passage and a straight spline at the other opposite end portion of said passage, the helical spline of said member engaging the helical spline of said first sleeve so that said member is rotatably and slidably mounted to said sleeve, said straight spline of said member engaging the straight spline of said driving sleeve, so that said driving sleeve is slidably but nonrotatably mounted to said member;

means for separating the clutch teeth of said driving sleeve from the clutch teeth of said driven sleeve by moving said driving sleeve in a first direction away from said driven sleeve when said driven sleeve rotates above a predetermined speed, said separating means including: an annular ring having an inner inclined surface; means for mounting said ring to said one end of said driving sleeve;

a plurality of arcuate centrifugal weight members disposed adjacent said ring, each of said weight members having an inclined surface; and

means for mounting said centrifugal weight members so that said inclined surfaces of said centrifugal weight members abut said inclined surfaces of said annular ring, said inclined surfaces operative to axially displace said annular ring and said driving sleeve in the direction of said narrowed portion of said housing when said driven sleeve rotates above said predetermined speed;

means for axially biasing said driven and driving sleeve so that their teeth are in an engaged position until said driven sleeve reaches said predetermined speed, said biasing means including: means forconnecting the first end of said housing first portion to the first end of said housing second portion, said connecting means including:

a biasing element disposed between the first end of said housing second portion and the first end of said housing first portion; and means for retaining said biasing elementbetween said first andsecond housing portion so that axial movement one direction of either portion of the housing with respect to the other will increase the biasing force;

means for keeping the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driven sleeve when said driving sleeve moves in the direction of said driven sleeve, said means includafirst means for biasing said member in the direction of said driving sleeve, said biasingmeans including a first spring axially disposed between said housing and said member, said spring having a spring constant (k and a second me'ansfor biasing said driving sleeve in the direction of said driven sleeve, said second biasing means including a second spring axially disposed between said housing and said driving sleeve, said spring having a spring constant (k which is greater than (k whereby when an axial force is applied to the driven sleeve gear teeth, in a first direction of the narrowed portion of said housing, said driven sleeve, said driving sleeve and said member move axially and rotatably in said first direction, said driving sleeve moving axially along the straight spline on said member and also following the movement of said member which follows the helical spline of said first sleeve causing said first spring and said second spring to compress so that when said axial force is removed, said second spring, having the greater spring constant (k will force said driving sleeve to move axially but nonrotatably in a second opposite direction along said straight spline on said member thereby allowing the driving and driven sleeves to keep the clutch teeth in engagement before the first spring, with the lowerspring constant, forces said members to move axially and rotatably in said second direction along the helical spline on said first sleeve.

8. In combination with an internal combustion engine of the type having a gear for starting rotation of the en gine crankshaft and a starter for rotating said engine gear, said starter including: a rotatable power shaft; a first sleeve coaxially, slidably and rotatably mounted on said shaft, said first sleeve adapted to operatively engage said power shaft and rotate therewith; a driven clutch sleeve coaxially, slidably and rotatably mounted on said first sleeve, said driven sleeve having radially extending gear teeth on one end and axially extending clutch teeth on the other end; a driving clutch sleeve coaxially, slidably and rotatably mounted on said first sleeve adjacent said driven sleeve, said driving sleeve having axially extending clutch teeth on one end which include surfaces engageable with said driven sleeve clutch teeth for transmitting torque between said driven and driving sleeves; means for separating the clutch teeth of said driving sleeve from the clutch teeth of said driven sleeve by moving said driving sleeve in a direction away from said driven sleeve when said driven sleeve rotates above a predetermined speed; wherein the improvement comprises:

means for keeping the clutch teeth of said driven sleeve in engagement with the clutch teeth of said driving sleeve when said driving sleeve moves in a direction of said driven sleeve. 9. The combination as recited in claim 8 wherein the means for keeping the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driven sleeve when said driving sleeve moves in the direction of said driven sleeve comprises:

a first means for biasing said driving sleeve in the direction of said driven sleeve; and

a second means for biasing said driving sleeve in the direction of said driven sleeve, said second biasing means exerting a greater biasing force on said driving sleeve than said first biasing means exerts on said driving sleeve,

whereby when an axial force is applied to the driven sleeve gear teeth, in a first direction, said driven and driving sleeves move axially and rotatably; and when. said force is removed, said second biasing means having the greater biasing force causes said driven and driving sleeves to move axially but nonrotatably with respect to said first sleeve in a second opposite direction before moving rotatably by action of said first biasing means thereby allowing the driving and driven sleeves to keep the clutch teeth in engagement when said driving sleeve moves in the direction of said driven sleeve.

10. Starter gearing comprising:

an elongated member having a central axis, an outside surface, and driving means on one portion of said outside surface;

a driven clutch sleeve coaxially, slidably and rotatably mounted on said member, said driven sleeve having radially extending gear teeth on one end and axially extending clutch teeth on the other end;

a driving sleeve coaxially disposed with respect to said member adjacent said driven sleeve, said driving sleeve having axially extending clutch teeth on one end which include surfaces engaged with said driven sleeve clutch teeth for transmitting torque between said driven and driving sleeves;

means for mounting said driving sleeve for biased axial and rotational movement with respect to said member;

means for separating the clutch teeth of said driven sleeve from the clutch teeth of said driving sleeve by moving said driving sleeve in a first direction away from said driven sleeve when said driven sleeve rotates above a predetermined speed; and

means for keeping the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driven sleeve when said driving sleeve and said driven sleeve, which have been axially disposed in said first direction, move in a direction opposite said first direction.

11. The combination as claimed in claim 10 wherein said means for keeping the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driven sleeve when said driving sleeve moves in a direction of said driven sleeve includes:

a housing having a passage therethrough, said passage having a narrow portion at one end, said narrow portion coaxially mounted to one end of said elongated member;

a cup shaped member having a central axis and an inside surface, said inside surface having a first portion coaxially disposed with said central axis and a second portion transverse to said central axis, said second portion having a first means for receiving the driving means on one portion of the outside surface of said elongated member, said first receiving means coaxially disposed with the driving means on one portion of the outside of said elongated member for communication therewith, said first portion having second means for receiving said mounting means of said driving sleeve for biased axial and rotational movement with respect to said elongated member and for axial but nonrotatable movement with respect to said driving sleeve;

a first means for biasing said cup shaped member into engagement with said driving sleeve; and

a second means for biasing said driving sleeve into engagement with said driven sleeve.

12. Starter gearing comprising:

an elongated member having a central axis;

a driven clutch sleeve coaxially, slidably and rotatably mounted on said member, said driven sleeve having radially extending gear teeth on one end and axially extending clutch teeth on the other end;

a driving clutch coaxially and slidably mounted on said member for limited and biased rotatable movement therewith, said driving sleeve disposed wherein the means for keeping the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driven sleeve includes:

means for biasing said driving sleeve in the direction of said driven sleeve, said biasing means including a first spring having a spring constant A- and a second spring having a spring constant k which is at least 1.5 times greater than k 

1. Starter gearing comprising: a shaft; a intermediate member having a forward end and a rearward end; means for mounting said intermediate member on said shaft, said means including: means for providing axial and rotational movement of said member mounted on said shaft; and means for biasing said member in the forward direction so that when a force is applied in the rearward direction, said member moves axially and rotatably in a rearward direction and when said force is removed, said member returns to its original position; a driving clutch sleeve having a forward and rearward end, said forward end having axially extending clutch teeth; means for mounting said driving sleeve on said intermediate member, said means including: means for providing axial movement of said driving sleeve with respect to said intermediate member; and means for biasing said driving sleeve in the forward direction so that when a force is applied in the rearward direction, said driving sleeve moves axially in a rearward direction and when said force is removed, said driving sleeve returns to its original position; a driven clutch sleeve having radially extending gear teeth on one end portion and axially extending clutch teeth on the opposite end; and means for mounting said driven sleeve on said shaft for rotational and axial movement with respect to said shaft, said driven sleeve disposed so that the clutch teeth of said driven sleeve engage said driving sleeve clutch teeth for transmitting torque between said driving sleeve and said driven sleeve to rotate said driven sleeve; whereby when a rearward force is applied to said driven sleeve, said driven sleeve and said driving sleeve move axially rearward with respect to said intermediate member and said intermediate member moves rotatably and axially rearward with respect to said shaft, so that when said rearward force is removed said driving clutch sleeve moves in a direction of said driven clutch sleeve while said mutually engageable clutch teeth are maintained in full engagement.
 2. The starter gearing recited in claim 1 wherein the means for biasing said intermediate member includes a spring having a spring constant k1 and wherein the means for biasing said driving sleeve includes a spring having a spring constant k2, which is greater than k1.
 3. The starter gearing recited in claim 2 wherein k2 is between 1.5 and 2.7 times the magnitude of k1.
 4. The starter gearing as recited in claim 3 wherein the means for mounting the intermediate member on the shaft for axial and rotational movement of said member includes a helical spline on one portion of said member.
 5. The starter gearing as reciTed in claim 4 wherein the means for mounting said driving sleeve on said intermediate member for axial movement of said driving sleeve with respect to said member includes a straight spline on said driving sleeve that mates with a straight spline on a portion of said member.
 6. The starter gearing as recited in claim 5 including: means for separating the clutch teeth of said driving sleeve from the clutch teeth of said driven sleeve by moving said driving sleeve in a first direction away from said driven sleeve when said driven sleeve rotates above a predetermined speed.
 7. Starter gearing comprising: a barrel shaped housing having a central axis and a passage therethrough, said housing having a first portion and a second portion axially aligned with said first portion; said second portion having a first end and an opposite end; said first portion having a first end and an opposite end having a narrowed portion; and a first sleeve having an outside end portion mounted to the narrowed portion of said housing, said first sleeve having a helical spline on the other outside end portion, and a straight spline on the inside surface of said sleeve; a second sleeve axially aligned with and adjacent to said first sleeve; said second sleeve connected at one end to one end of said first sleeve; a driving sleeve coaxially disposed with respect to said first and second sleeve, said driving sleeve having a straight spline on one portion of the outside surface and axially extending clutch teeth on one end; a driven sleeve coaxially disposed and mounted to said second sleeve adjacent to said driving sleeve, said driven sleeve having radially extending gear teeth on one end and axially extending clutch teeth on the other end which engage said driving sleeve clutch teeth for transmitting torque between said driving and driven sleeves to rotate said driven sleeve, said driven sleeve having an annular recess formed on the inside surface of said other end; a member moveably mounted on said first sleeve, said member having a first end portion, a second opposite end portion, a passage therethrough, a helical spline at said first end portion of said passage and a straight spline at the other opposite end portion of said passage, the helical spline of said member engaging the helical spline of said first sleeve so that said member is rotatably and slidably mounted to said sleeve, said straight spline of said member engaging the straight spline of said driving sleeve, so that said driving sleeve is slidably but nonrotatably mounted to said member; means for separating the clutch teeth of said driving sleeve from the clutch teeth of said driven sleeve by moving said driving sleeve in a first direction away from said driven sleeve when said driven sleeve rotates above a predetermined speed, said separating means including: an annular ring having an inner inclined surface; means for mounting said ring to said one end of said driving sleeve; a plurality of arcuate centrifugal weight members disposed adjacent said ring, each of said weight members having an inclined surface; and means for mounting said centrifugal weight members so that said inclined surfaces of said centrifugal weight members abut said inclined surfaces of said annular ring, said inclined surfaces operative to axially displace said annular ring and said driving sleeve in the direction of said narrowed portion of said housing when said driven sleeve rotates above said predetermined speed; means for axially biasing said driven and driving sleeve so that their teeth are in an engaged position until said driven sleeve reaches said predetermined speed, said biasing means including: means for connecting the first end of said housing first portion to the first end of said housing second portion, said connecting means including: a biasing element disposed between the first end of said housing second portion and the first end of said housing first portion; and Means for retaining said biasing element between said first and second housing portion so that axial movement one direction of either portion of the housing with respect to the other will increase the biasing force; means for keeping the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driven sleeve when said driving sleeve moves in the direction of said driven sleeve, said means including: a first means for biasing said member in the direction of said driving sleeve, said biasing means including a first spring axially disposed between said housing and said member, said spring having a spring constant (k2); and a second means for biasing said driving sleeve in the direction of said driven sleeve, said second biasing means including a second spring axially disposed between said housing and said driving sleeve, said spring having a spring constant (k2) which is greater than (k1); whereby when an axial force is applied to the driven sleeve gear teeth, in a first direction of the narrowed portion of said housing, said driven sleeve, said driving sleeve and said member move axially and rotatably in said first direction, said driving sleeve moving axially along the straight spline on said member and also following the movement of said member which follows the helical spline of said first sleeve causing said first spring and said second spring to compress so that when said axial force is removed, said second spring, having the greater spring constant (k2), will force said driving sleeve to move axially but nonrotatably in a second opposite direction along said straight spline on said member thereby allowing the driving and driven sleeves to keep the clutch teeth in engagement before the first spring, with the lower spring constant, forces said members to move axially and rotatably in said second direction along the helical spline on said first sleeve.
 8. In combination with an internal combustion engine of the type having a gear for starting rotation of the engine crankshaft and a starter for rotating said engine gear, said starter including: a rotatable power shaft; a first sleeve coaxially, slidably and rotatably mounted on said shaft, said first sleeve adapted to operatively engage said power shaft and rotate therewith; a driven clutch sleeve coaxially, slidably and rotatably mounted on said first sleeve, said driven sleeve having radially extending gear teeth on one end and axially extending clutch teeth on the other end; a driving clutch sleeve coaxially, slidably and rotatably mounted on said first sleeve adjacent said driven sleeve, said driving sleeve having axially extending clutch teeth on one end which include surfaces engageable with said driven sleeve clutch teeth for transmitting torque between said driven and driving sleeves; means for separating the clutch teeth of said driving sleeve from the clutch teeth of said driven sleeve by moving said driving sleeve in a direction away from said driven sleeve when said driven sleeve rotates above a predetermined speed; wherein the improvement comprises: means for keeping the clutch teeth of said driven sleeve in engagement with the clutch teeth of said driving sleeve when said driving sleeve moves in a direction of said driven sleeve.
 9. The combination as recited in claim 8 wherein the means for keeping the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driven sleeve when said driving sleeve moves in the direction of said driven sleeve comprises: a first means for biasing said driving sleeve in the direction of said driven sleeve; and a second means for biasing said driving sleeve in the direction of said driven sleeve, said second biasing means exerting a greater biasing force on said driving sleeve than said first biasing means exerts on said driving sleeve, whereby when an axial force is applied to the driven sleeve gear teeth, in a first direction, said driven and driving sleeves move axially and rotatably; and when said force is removed, said second biasing means having the greater biasing force causes said driven and driving sleeves to move axially but nonrotatably with respect to said first sleeve in a second opposite direction before moving rotatably by action of said first biasing means thereby allowing the driving and driven sleeves to keep the clutch teeth in engagement when said driving sleeve moves in the direction of said driven sleeve.
 10. Starter gearing comprising: an elongated member having a central axis, an outside surface, and driving means on one portion of said outside surface; a driven clutch sleeve coaxially, slidably and rotatably mounted on said member, said driven sleeve having radially extending gear teeth on one end and axially extending clutch teeth on the other end; a driving sleeve coaxially disposed with respect to said member adjacent said driven sleeve, said driving sleeve having axially extending clutch teeth on one end which include surfaces engaged with said driven sleeve clutch teeth for transmitting torque between said driven and driving sleeves; means for mounting said driving sleeve for biased axial and rotational movement with respect to said member; means for separating the clutch teeth of said driven sleeve from the clutch teeth of said driving sleeve by moving said driving sleeve in a first direction away from said driven sleeve when said driven sleeve rotates above a predetermined speed; and means for keeping the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driven sleeve when said driving sleeve and said driven sleeve, which have been axially disposed in said first direction, move in a direction opposite said first direction.
 11. The combination as claimed in claim 10 wherein said means for keeping the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driven sleeve when said driving sleeve moves in a direction of said driven sleeve includes: a housing having a passage therethrough, said passage having a narrow portion at one end, said narrow portion coaxially mounted to one end of said elongated member; a cup shaped member having a central axis and an inside surface, said inside surface having a first portion coaxially disposed with said central axis and a second portion transverse to said central axis, said second portion having a first means for receiving the driving means on one portion of the outside surface of said elongated member, said first receiving means coaxially disposed with the driving means on one portion of the outside of said elongated member for communication therewith, said first portion having second means for receiving said mounting means of said driving sleeve for biased axial and rotational movement with respect to said elongated member and for axial but nonrotatable movement with respect to said driving sleeve; a first means for biasing said cup shaped member into engagement with said driving sleeve; and a second means for biasing said driving sleeve into engagement with said driven sleeve.
 12. Starter gearing comprising: an elongated member having a central axis; a driven clutch sleeve coaxially, slidably and rotatably mounted on said member, said driven sleeve having radially extending gear teeth on one end and axially extending clutch teeth on the other end; a driving clutch coaxially and slidably mounted on said member for limited and biased rotatable movement therewith, said driving sleeve disposed adjacent said driven sleeve and having axially extending clutch teeth on one end which include surfaces engaged with said driven sleeve clutch teeth for transmitting torque between said driven and driving sleeves; and means for keeping the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driven sleeve when said driving sleeve moves in a direction Of said driven sleeve.
 13. Engine starter gearing as recited in claim 12 wherein the means for keeping the clutch teeth of said driving sleeve in engagement with the clutch teeth of said driven sleeve includes: means for biasing said driving sleeve in the direction of said driven sleeve, said biasing means including a first spring having a spring constant k1 and a second spring having a spring constant k2 which is at least 1.5 times greater than k1. 